Java image compression for PNG image using imageio

I am using the code given below for image compression of jpeg/png/gif images. In the case of png image instead of decreasing size, size of image is increasing. Ex: My image size was 824 KB and after compression, its size becomes 1.2 MB. Image size should decrease or remains the same but should not increase at least. What should I do in my code to solve this?

   File input = new File("digital_image_processing.png");
   BufferedImage image = ImageIO.read(input);

   File compressedImageFile = new File("compress.png");  
   OutputStream os = new FileOutputStream(compressedImageFile);

   Iterator<ImageWriter>writers = ImageIO.getImageWritersByFormatName("png");
   ImageWriter writer = (ImageWriter) writers.next();

   ImageOutputStream ios = ImageIO.createImageOutputStream(os);
   writer.setOutput(ios);

   ImageWriteParam imageWriteParam = writer.getDefaultWriteParam();

   if (imageWriteParam.canWriteCompressed()) {
      imageWriteParam.setCompressionMode(ImageWriteParam.MODE_EXPLICIT);
      if (imageWriteParam.getCompressionType() == null) {
          imageWriteParam.setCompressionType(imageWriteParam.getCompressionTypes()[0]);
      }
      imageWriteParam.setCompressionQuality(imageQuality);
   }

   writer.write(null, new IIOImage(image, null, null), imageWriteParam);